Bactericidal/permeability increasing factor (BPI) may downregulate the inflammatory host response to endotoxin. BPI, a 55 kD molecule found in neutrophil granules and membranes, has antibacterial effects and antiendotoxic activities. We have undertaken a blinded, placebo controlled study of BPI in canines infected with E.coli peritonitis. Like previous studies using the canine model, we will monitor 28-day survival and serial hemodynamics, and blood culture and endotoxin level. This experiment will clarify whether this drug could be beneficial in humans with septic shock.